Automatic Transmission Overdrive

[tekjones83]

I have a 1995 Mitsubishi Mighty Max SWB 2.4L Auto. The trans won't go into overdrive what can I do to fix it cheaply I don't want to send it to a trans shop.

[pennyman1]

there is a sensor on the intake manifold near the throttle body that closes when the engine is warmed up thats bad - take the wire off the sensor and ground it to the intake on one of the lugs on the manifold under the throttle body and the O/D will work any time the button on the shifter does not lock it out.

[tekjones83]

Ok Thank you and I will try that when it is up and running after I replace the seals and timing belts.

[tekjones83]

I found a single wire not connected to anything looks like it broke off from a something near the throttle body but it is just laying there and is that maybe the wire I need to ground to the intake?

[pennyman1]

try grounding it and see - it could be the wire for the O/D sensor.

[tekjones83]

will do Thanks!

[tekjones83]

You wouldn't know the color of the wire do you because I found out the broken wire was the connector was still on the bottom temp sensor I believe it is the temp sensor but I could be wrong lol but the point is the wire was broke from the connector and I fixed that but no change in a/t overdrive not engaging at all

[pennyman1]

should be a black wire - to be sure, look in our manual section for your truck.

[tekjones83]

anyone got a pic of it so I would know what i am looking for or something sorry im just really confused and there are 3 sensors. 2 on the water outlet where the thermostat sits and one on the intake under the thermostat housing. Am i close to it?

[tekjones83]

Just wanted to say I found the wire and grounded it to the intake and still no overdrive :( but I did find the A/T ECM and I took it out and opened it and it has hot marks and corrosion where the electronics are soldered to the board in some places so I believe the ECM is toast or half-way working. So one the hunt for a new or used one.

[pennyman1]

got to fix that first - thats the trouble with electronics, they don't work after the magic smoke escapes...

[tekjones83]

Yea I know right hahaha :P

[Can1991Ram]

Anyone have a source for the tranny ecu?

[noahwins]

RockAuto.com has them rebuilt. Or car-part.com or row52.com for a used one.

[mitchi]

Will you please show some pictures???????????????????

[Can1991Ram]

I looked on rockauto but have no idea what it is called.

[Can1991Ram]

from what I have read on A500.. you can actually you a switch to lock the converter and overdrive if you don't want to replace the control unit. This is what people do when they swap the A500 and A518 into older vehicles.

[mitchi]

What and where is the tranny ecu?

[Rperales25]

there is a sensor on the intake manifold near the throttle body that closes when the engine is warmed up thats bad - take the wire off the sensor and ground it to the intake on one of the lugs on the manifold under the throttle body and the O/D will work any time the button on the shifter does not lock it out.

Is it called a thermo switch?

[geezer101]

Is it called a thermo switch?

Yes, but be sure if you are ordering a replacement unit you specify what it's for or you may end up with a temperature gauge sender unit (it happens all the time...)

[Chargerx3]

Thread needs pics.

[MrPaco]

Yes, but be sure if you are ordering a replacement unit you specify what it's for or you may end up with a temperature gauge sender unit (it happens all the time...)

My shop ordered the temperature gauge sender unit, they got the thermo switch. twice

[Chargerx3]

Wanted to follow up on this. Did this fix your issue?

[MrPaco]

Wanted to follow up on this. Did this fix your issue?
Not sure if you are referring to my issue, or someone one of the other earlier posts on the thread. But yes it was resolved, but not in a way that sheds much light on the sensors question.
After trying two different temp gauge sensors, both of which turned out ot be on/off type sensors and were giving crazy readings (back and forth between all the way cold and all the way hot), put the old sensor back in and replaced the thermostat. Temperature readings went back to normal, turns out the sensor was fine the whole time, but the thermostat was stuck open so the engine temperature never got hot enough for the gauge to show a normal reading.

[SyrsKnight]

Hi, i have an issue that i cant seem to find a solution for with a 1990 Mitsubishi mighty max with i believe the same type motor and transmission (with overdrive) but instead of it not going into overdrive, which it does do, i believe, mine works fine until i am at driving speed,lets say 45mph, then it starts jerking, slightly at first then alittle harder. It almost feels like it either jumps out of gear for a second or bad gas (which i know isnt the issue) or like a vacuum line has come off somewhere. It only does this at 45 mph & above, but pulls good when accelerating at any speed. Just when its at a steady speed it does it. What could this be & how do i fix it? Also, the linkage has been tampered with but i have it set properly now. Thanks!

[camoit]

That sounds like the linkage adjustment on the engine side.
Also change the fuel filter.

[SyrsKnight]

Yes i have changed the fuel filter. I've adjusted the linkage on not only the engine side but the column side as well. They guy i bought the truck from told me that for whatever reason he tried to adjust the linkage on the steering column and as he done so the plastic/rubber bushings & a white spacer thing broke. Which it was as he said & incredibly loose. Even tho i adjusted it correctly and replaced the so called broken & missing parts it still is somewhat loose & still i have to crank in neutral. Finally it feels like its not in overdrive at crusing speeds 45 mph or more, like it keeps trying to change into overdrive or the next gear but it just cant. There is no difference i can feel when pushing the overdrive button on or off.

[SyrsKnight]

Yes i have changed the fuel filter. I've adjusted the linkage on not only the engine side but the column side as well. They guy i bought the truck from told me that for whatever reason he tried to adjust the linkage on the steering column and as he done so the plastic/rubber bushings & a white spacer thing broke. Which it was as he said & incredibly loose. Even tho i adjusted it correctly and replaced the so called broken & missing parts it still is somewhat loose & still i have to crank in neutral. Finally it feels like its not in overdrive at crusing speeds 45 mph or more, like it keeps trying to change into overdrive or the next gear but it just cant. There is no difference i can feel when pushing the overdrive button on or off.